1. Field of the Invention
The present invention relates to power management in computer systems and processors. More specifically, the present invention relates to an apparatus and operating method for managing application of power to a circuit card. 2. Description of the Related Art
Present-day notebook computers commonly include a processor mounted on a motherboard and a case supporting a keyboard and display. Data storage is commonly supplied by multiple magnetic disk drives including a hard drive and a floppy drive. One or more PCMCIA cards (PCCars) are optionally included in a notebook computer to perform various functions. Common PCCards in notebook computers include communication interfaces such as modems and network interface cards. While networking and modem PCCards are highly useful and add important functionality to notebook computers, they disadvantageously consume power whether in use or inactive.
Power consumption of the networking and modem PCCard is generally not a problem when the notebook computer and user are located near a local area network (LAN) or telephone outlet since a wall socket is normally accessible to power the notebook computer. However many notebook computer users commonly leave the communications interface PCCard inserted into the notebook computer at all times, treating the PCCard as a built-in component, whether the notebook computer is connected to the LAN or telephone output and powered by a wall socket or the notebook computer is disconnected from communications lines and an external power source.
The operating practices of many users further increases the power drain and shortens the battery life of the notebook computer. For example, many users configure a notebook computer system to automatically start software applications that utilize the communications interfaces by default, for example on power-up of the notebook computer.
Various techniques have been developed to reduce the power consumption and extend the battery life of notebook computers. An Advanced Configuration and Power Interface (ACPI) specification has been developed to implement motherboard configuration and power management functions using suitable cost/function tradeoffs in personal computers including desktop, mobile, home and server computers. The ACPI specification also enhances power management functionality and robustness, facilitates and accelerates industry-wide implementation of power management, and creates a robust interface for configuring motherboard devices.
Specifically with regard to PCCard power consumption, including communication interface consumption, many notebook computers include power management techniques that allow a PCCard slot to be disabled. In addition, manufacturers of PCCards use low power consumption components to conserve battery resources.
Conventional power management techniques successfully reduce power consumption in portable computers often by one-half or more depending on the device powered by the PCCard and the power management techniques that is used. However, a computer having a communication interface PCCard connected to a PCCard slot in the computer continues to draw current and consume power even when the PCCard is disconnected from a network. In some systems, power management places the PCCard in a lower power state but the PCCard continues to draw power, reducing the time that the battery is suitably charged for execution.